1. Field of the invention
This invention has to do with continuous production bag making machines that produce plastic bags from sheet or tube feed stock. The invention is an improvement to rotary hole cutters used in such bag making machines.
2. Description of Related Art
Rotary hole cutters having a configuration similar to that shown in the general drawing figures are known. Circular cutouts have previously been made in stock using roller wheels pressing the stock against a knife edge. When this technology is used in cutting holes in plastic bag material, however, where two layers of material need be cut at once, it has been found that the film retention means in the area confined to the hole to be cut were inadequate to hold the film. With the film insecurely held, there were often instances of erratic hole shapes, cut wrinkles, uncut sections of film where, for instance, the film was doubled over or the "wave" propagated by the wheels doubled over or the "wave" propagated by the wheels doubled over the film. Applicant has solved the problem of erratic cuts by improved methods and apparatus for holding the film to be cut in place more securely once the cutting cycle has begun.